Re: [PATCH bpf-next 1/3] bpf,s390: introduce emit_store_stack_imm64() for trampoline

[Menglong Dong <menglong.dong@linux.dev>]

On 2026/2/23 19:44 Ilya Leoshkevich <iii@linux.ibm.com> write:
> 
> On 2/23/26 09:40, Menglong Dong wrote:
> > Introduce a helper to store 64-bit immediate on the trampoline stack with
> > a help of a register.
> >
> > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
> > ---
> >   arch/s390/net/bpf_jit_comp.c | 27 +++++++++++----------------
> >   1 file changed, 11 insertions(+), 16 deletions(-)
> 
> [...]
> 
> > @@ -2743,18 +2747,9 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
> >   	 * arg_cnt = m->nr_args;
> >   	 */
> >   
> > -	if (flags & BPF_TRAMP_F_IP_ARG) {
> > -		/* %r0 = func_addr */
> > -		load_imm64(jit, REG_0, (u64)func_addr);
> > -		/* stg %r0,ip_off(%r15) */
> > -		EMIT6_DISP_LH(0xe3000000, 0x0024, REG_0, REG_0, REG_15,
> > -			      tjit->ip_off);
> > -	}
> > -	/* lghi %r0,nr_bpf_args */
> > -	EMIT4_IMM(0xa7090000, REG_0, nr_bpf_args);
> 
> LGHI is more space-efficient than load_imm64(), can we keep it open-coded?

OK, I can keep this lghi instruction as it was.

Thanks for your reviewing :)

> 
> With this changed:
> 
> Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
> 
> 
>